The method of Sādhana (spiritual practice) is known only through the Guru (spiritual teacher). Describing the method of any sādhana in scriptures only leads to misuse and malpractice, because a sādhaka (practitioner) cannot correctly understand the process merely by reading about it in texts. It is only through a Guru that one can truly comprehend it.
This is the reason why I have not described the methods of sādhana in my texts.
In the Bhagavad Gītā, Bhagavān Śrī Kṛṣṇa has stated:
“Apāne guhati prāṇaṃ prāṇāpāna-samānayoḥ”
(One should merge Apāna Vāyu into Prāṇa Vāyu, and Prāṇa Vāyu into Apāna Vāyu).
Can anyone truly understand this process without the guidance of a Guru?
— Mahāmahopādhyāya Paṇḍita Gopīnātha Kavirāja